Efficacy of Nilotinib in a CML Patient Expressing the Three-way Complex Variant Translocation t(2;9;22)

Chronic myelogenous leukemia (CML) is characterized by the presence of the Philadelphia chromosome, resulting from the reciprocal translocation involving chromosomes 9 and 22. About 5-10% of newly diagnosed patients in chronic-phase (CP) CML show complex additional chromosomal aberrations (ACA), that may involve one or more chromosomes in addition to 9 and 22. Data concerning the prognostic significance of ACA in CP-CML subjects at diagnosis are controversial. Furthermore, there is no evidence showing that selection of imatinib (IM) or second-generation tyrosine kinase inhibitors (2G-TKI) would be of benefit for these patients.

We report the three-way complex variant translocation t(2;9;22) in a CP-CML patient. Conventional cytogenetic analysis was employed to identify the ACA. Multiplex reverse transcription-PCR was used to identify the BCR-ABL1 transcript and its levels were measured using quantitative real-time-PCR. This rare ACA t(2;9;22) in our young patient displayed primary resistance to IM, but was responsive to second-line treatment with nilotinib.

CP-CML patients exhibiting this rare aberration at diagnosis may benefit from a 2G-TKI therapy compared to IM.